ICAME Conference Report: Craiglands Hotel, Ilkley, Yorks 6-12 May 1991

ICAME is the annual get together of corpus linguists. This year's, (the twelfth) was hosted by Leeds University at a rather nice decayed Victorian hotel on the edge of Ilkley Moor and enjoyed excellent weather, the usual relaxed atmosphere and the usual extraordinary array of research reports, which can only be very briefly noticed in this report. As usual, there were about 50 invited delegates, most of whom knew each other well, and a few rather bemused looking non-Europeans, notably Mitch Marcus (Penn State) and Louise Guthrie (New Mexico SU). The social programme included an outing to historic Haworth by steam train which, alas, your correspondent had to forgo in order to attend to other TEI business, and large amounts of good Yorkshire cooking, which he did not.

For the first time, the organising committee had included a so- called open day, to which a number of interested parties, supposedly keen to find out what this corpus-linguistics racket was all about, had been invited. As curtain raiser to this event, I was invited to present a TEI status report, which I did at break neck speed, and Jeremy Clear (OUP) to describe the British National Corpus project, which he did at a more relaxed pace. The open day itself included brief presentations from Stig Johansson (Oslo), on the history of ICAME since its foundation in 1973, from Antoinette Renouf (Birmingham) on the basic design problems of corpus building, from Sid Greenbaum (London) on the design and implementation of the new co-operative International Corpus of English project, from Eric Atwell (Leeds) on the kinds of parsing systems which corpus linguistics made possible, from Jan van Aarts (Nijmegen) on the Nijmegen approach to computational linguistics, from John Sinclair (Birmingham) on the revolutionary effect of corpus linguistics on lexicography and on language teaching, from Gerry Knowles (Lancaster) on the particular problems of representing spoken language in a corpus and from Knut Hofland (Bergen) on the technical services provided for ICAME at Bergen. While none of these speakers said anything particularly new, several of them (notably van Aarts, Renouf and Sinclair) managed to convey very well what is distinctive and important about the field. As far as I could tell, most of the ICAME community was a bit dubious about the usefulness of the Open Day. For outsiders wishing to get up to speed on why corpus linguistics is interesting and why it matters however, I would judge it a notable success.

Corpus linguistics is, of course, all about analysing large corpora of real world texts. To do this properly, you probably need a good lexicon, and you will certainly finish up with one, if you do the job properly. Not surprisingly therefore, the conference proper began with a series of papers about electronic lexica of various flavours, ranging from the CELEX database (Richard Piepenbrock, Nijmegen) in which a vast array of information about three languages (Dutch, English and German) is stored in a relational database, to the experimental word-sense lattices traced by Willem Meijs' Amsterdam research teams from the LDOCE definitions. Work based on this, surely by now the most analysed of all mrds, was also described by Jacques Noel (Liege) and by Louise Guthrie (NMSU). The former had been comparing word-senses in Cobuild and LDOCE, while the latter had been trying to distinguish word senses by collocative evidence from the LDOCE definition texts: although well presented and argued, her conclusions were rather unsurprising (highly domain specific texts are easier to disambiguate than the other sort), and to base any conclusions about language in general on the very artificial language of the LDOCE definition texts seems rather dubious.

The traditional ICAME researcher first quantifies some unsuspected pattern of variation in linguistic usage and then speculates as to its causes. Karin Aijmer (Lund), for example, reported on various kinds of `opener's in the 100 or so telephone conversations in the London-Lund Corpus, in an attempt to identify what she called routinisation patterns. In a rather more sophisticated analysis, Bent Altenberg (Lund) reported on a frequency analysis of recurrent word class combinations in the same corpus, and Pieter de Haan (Nijmegen) on patterns of sentence length occurrences within various kinds of written texts.

Although attendance at ICAME is by invitation only, an honourable tradition is to extend that invitation to anyone who is doing something at all related to corpus work, even a mere computer scientist like Jim Cowie (Stirling) who began his very interesting paper on automatic indexing with the heretical assertion that restructing the type of text analysed was essential if you wanted to do anything at all in NLP. The object of his research was to identify birds, plants etc. by means of descriptive fragments of text and his method, which relied on identifying roles for parts of the text as objects, parts, properties and values, both highly suggestive for other lines of research and eminently pragmatic. A similarly esoteric, but only potentially fruitful, line of enquiry was suggested by Eric Atwell's report on some attempts to apply neural networks to the task of linguistic parsing.

Another nice ICAME tradition is the encouragement of young turks and research assistants, who, when not acutely terrified, are often very good at presenting new approaches and techniques. This year's initiates included Simon Botley (Lancaster), who presented a rather dodgy formalism for the representation of anaphoric chains, Paul Gorman (Aberystwyth) who had translated CLAWS2 into ADA and almost persuaded me that this was a good idea, Christine Johansson (Uppsala) who had been comparing `of which' with `whose' - almost certainly not a good idea and Paul Rayson & Andrew Wilson (also Lancaster) who had souped up General Enquirer to do some rather more sophisticated content analysis of market research survey results by using Claws2 to parse it.

Two immaculately designed and presented papers concerned work at the boundary between spoken speech as recorded by an acoustic trace and by transcription: Anne Wichmann (IBM) presented an analysis of `falls' in the London-Lund corpus, a notorious area of disagreement between transcribers. Her elicitation experiment tended to show that there was a perceived continuity between high and low falls which transcribers could not therefore categorise. Gerry Knowles (Lancaster) proposed a model for speech transcription, in which perceived phonemic categories formed an intermediate mapping between text and acoustic data. Speech transcriptions require a compromise between patterns that can be computed from text and interpretations derived from acoustic data.

High spots of the conference for me were the presentations from O'Donoghue (Leeds) and Marcus. If there is anyone around who still doesn't believe in systemic functional grammar, Tim O'Donoghue's presentation should have converted him or her. He reported the results of comparing statistical properties of a set of parse- trees randomly generated from the systemic grammar developed by Fawcett and Tucker for the Polytechnic of Wales Corpus with the parse trees found in the same (hand-)parsed corpus itself. The high degree of semantic knowledge in the grammar was cited to explain some very close correlations while some equally large disparities were attributed to the specialised nature of the texts in the corpus.

Mitch Marcus (Penn State) gave a whirlwind tour of the new burgeoning of corpus linguistics (they call it `stochastic methods') in the US, and made no bones about its opportunistic nature or or funding priorities. Incidentally providing the conference with one of its best jokes, when remarking of the ACL/DCI, the Linguistics Data Consortium etc. "People want to do this work extremely badly, and they need syntactic corpora to do it", he described the methods and design goals of the Penn Treebank project, stressing its engineering aspects and providing some very impressive statistics about its performance.

Several presentations and one evening discussion session concerned the new `International Corpus of English' or ICE project. Laurie Bauer (Victoria University) described its New Zealand component in one presentation, while Chuck Meyer (UMass) described some software developed to tag it (using Interleaf) in another. The most interesting of these however was from And Rosta (London) who is largely responsible for ICE's original and, for my taste, rather baroque encoding scheme: itvtook the form of a detailed point by point comparison between this and the TEI scheme with a view to assessing the possibility of converting between them. The verdict was largely positive, though he identified several points where TEI was lacking, some of which (notably the inability to tag uncertainty of tag assignment and a whole raft of problems in tagging spoken material) should certainly be addressed and all of which provided very useful and constructive criticisms.

There was a general feeling that standardisation of linguistic annotation (which corpus linguists confusingly insist on calling `tagging') was long overdue. Marcus pointed out that the LOB corpus had used 87 different tags for part of speech, LOB had upped this to 135, the new UCREL set had 166 and the London Lund Corpus 197. In Nijmegen, the TOSCA group has an entirely different tagset of around 200 items which has been adopted and, inevitably, increased by the ICE project. It seems to me that someone should at least try to see whether these various tagsets can in fact be harmonised using the TEI recommendations, or at least compared with the draft TEI starter set described in TEI AI1 W2. I also think that someone should at least try to see how successful the feature-structure mechanisms are at dealing with systemic networks of the POW kind.